High-Speed Cylindrical Grinding Research Articles

Research on Cloud-Edge-Device Collaborative Intelligent Monitoring System of Grinding Wheel Wear State for High-Speed Cylindrical Grinding of Bearing Rings

Aiming at the problems of grinding wheel wear during high-speed cylindrical grinding, communication delays, and slow response during data acquisition, processing, and system operation, an intelligent online monitoring technology frame for CNC manufacturing units is proposed, incorporating a real-time-perception grinding mechanism and a cloud-edge device. Based on the grinding data and grinding wheel wear mechanism, a monitoring model using multi-sensor information fusion is constructed to assess the grinding wheel wear state. In addition, edge data acquisition and online monitoring software have been developed to improve the speed of data transmission and processing. Finally, based on the proposed framework, a cloud-edge device collaborative intelligent monitoring system for assessing grinding wheel wear during high-speed cylindrical grinding of bearing rings is constructed. It improves the grinding quality and efficiency, reduces the grinding cost, and incorporates remote control functionality.

Chatter reliability of high speed cylindrical grinding with uncertain parameters

Cylindrical grinding is commonly used as the final process of machining, but its quality and efficiency are often limited by chatter phenomenon. Many research show that the result from conventional chatter analysis by using the deterministic parameters is not consistent with the practical working condition and the chatter reliability prediction in high speed cylindrical grinding with uncertain parameters is studied in this paper. The dynamic model of the cylindrical grinding system is established, and uncertain parameters such as mass, stiffness and damping coefficient are introduced, and the stability lobe diagrams with uncertain parameters were obtained. The reliability model of the grinding system was established, and the reliability was solved by using the Monte Carlo simulation method, the improved first-order second-moment method and the second-order second-moment method, respectively. Then, the chatter-free reliability of the system was predicted by using the reliability lobe diagram. The accuracy of the grinding reliability prediction results is verified by the experiment results. Furthermore, the Monte Carlo sensitivity analysis method is used to study the influence of random parameters on the grinding system, and the results show that the variation of modal mass has the greatest influence on the reliability of the grinding system.

Effect of process parameters on hardness and microstructure of 18CrNiMo7-6 carburized steel in high-speed cylindrical grinding

Effect of process parameters on hardness and microstructure of 18CrNiMo7-6 carburized steel in high-speed cylindrical grinding

Modeling and simulation of high-speed cylindrical grinding based on 3D grinding wheel topography

The purpose of this paper is to establish a 3D virtual grinding wheel to illustrate the high-speed cylindrical grinding process of difficult-to-machine materials under various process parameters. Based on Monte Carlo method, the abrasive grain is modeled cutting spherical solid with random planes, and the random distribution of grains is obtained based on the virtual grid method. Then the grinding wheel topography is trimmed to adjust the protrusion height of abrasive grains. The simulations of high-speed cylindrical grinding under different grinding conditions are carried out considering the thermomechanical coupling effect of grinding wheel and workpiece. The 3D grinding wheel is validated by analyzing the grinding force ratio. The effects of cutting depth on the grinding performance, such as grinding force, workpiece temperature, effective stress and surface quality, are discussed. The results show that a smaller depth of grinding is beneficial for better surface quality.

Effect of Grinding Conditions of a TC4 Titanium Alloy on its Residual Surface Stresses

The grindability of titanium alloys that are classified as hard-to-machine materials is studied in high-speed cylindrical grinding using a cubic boron nitride (CBN) wheel. The investigation is concerned with residual surface stresses, including the construction of its empirical model, orthogonal experiments with a CBN grinding wheel at a speed of 45–150 m/s, and prediction with the back propagation (BP) network. The results of residual surface stress measurements obtained in grinding experiments and simulation analysis for five sets of grinding conditions are compared, it can be seen that the empirical model is partially applicable to a Ti-6Al-4V titanium alloy (TC4) under examined grinding conditions. Generally, the calculation results with the empirical model exhibit a significant deviation from the data of actual measurements in some cases. The BP network possesses the function of complex nonlinear mapping and adaptive learning. So the BP network is adopted to predict the relation between residual surface stresses and three key grinding conditions accurately enough. The accuracy of the network is verified, which lays the foundation for its in practical application.

Experimental Study on Roundness of High-Speed Cylindrical Grinding for 20CrMnTi Alloy Steel

In order to reduce the roundness error of cylindrical grinding of shaft parts for 20CrMnTi alloy steel, the related experiments of high-speed cylindrical grinding are carried out and the influence of grinding parameters on roundness is analyzed. Based on the analysis of experimental data the conclusions are as follows: The influence of grinding wheel speed on work-piece roundness is not apparent, but the influence of work-piece speed and grinding depth on roundness is very significant. Based on high-speed grinding experiments the prediction model of cylindrical grinding for 20CrMnTi alloy steel is established by using of regression analysis method of least square. Based on the analysis of the roundness prediction model of cylindrical grinding the conclusions are as follows: The roundness error of cylindrical grinding parts will become lager with the increase of work-piece speed, grinding depth and grinding wheel speed.

A Theoretical Model of Grinding Force and its Simulation

Aiming at the axle material 30CrMoA high speed cylindrical grinding force calculation problems, a consideration of plowing force grinding force model is established based on the Werner’s theory model of grinding force, and the friction force and plowing force coefficient is defined as variable parameters. On the basis of the finite element analysis software DEFORM-3D, a high speed cylindrical grinding simulation model method is presented.Through the theoretical value and simulation value contrast, a mutual authentication of grinding force model is proposed. According to the simulation analysis results of grinding force and grinding wheel speed, grinding depth and the relationship between the workpiece speed, theoretical and technical guidance for the grinding force calculation and the selection of grinding process parameters are provided.

The Design Study of High-Speed Cylindrical Grinding Machine Transmission System

In mechanical processing, according to the requirements of components’ high surface quality, this paper makes a structure design of high-speed cylindrical grinding machine transmission system. Such structure is mainly used in high-speed grinding and powerful grinding, so as to improve the grinding efficiency. The design provides a certain basis for the further research of grinding machine structure.

Phase transformation in high-speed cylindrical grinding of SiC and its effects on residual stresses

Recently, the polytype transformation of SiC has been studied at temperatures over 2000K or at high pressures. However, there are no theoretical or experimental works exploring phase transformation during grinding process of SiC to date. In this work, the grinding characteristics such as temperature rise, high dynamic pressure and shock effect are compared with conditions for phase transition. For the first time, X-ray diffraction analysis of ground SiC under different machining conditions reveals that phase transition in high-speed cylindrical grinding occurs and strongly affects the residual stresses on the surface layer. Furthermore, a way to reduce the residual stresses by a combination of the elevated grinding wheel velocity and the higher workpiece speed is proposed.

The Characteristics of High-Speed Cylindrical Grinding of Silicon Carbide and its Influence on the Surface Layer

There has been increased interest in the use of advanced ceramic materials such as silicon carbide in the recent past, due to its unique physical and mechanical properties. However, the increase of the machining rate relies on the understanding of material removal mechanism on the microstructural scale and the relationship between the grinding characteristics and formation of surface/subsurface machining-induced damage. In this paper, grinding characteristics and surface integrity of SiC ground with diamond wheel on cylindrical grinding machine have been investigated. The grinding chip and the ground surface damage have been studied with scanning electron microscope (SEM). In particular the residual stress distribution has been analyzed by a single exposure technique d - sin2 (Ψ) method with the aid of powder X-ray diffractometer.

A Practical Study on the Surface Integrity of High-Speed Cylindrical Grinding of SiC

In order to reconcile the contradiction between the ceramic grinding efficiency and surface integrity, high-speed grinding with diamond grinding wheel is supposed to be a solution. In this paper, first of all, a normal grinding force model is proposed based on the consideration of the material property and the grinding process parameters. It can be seen that an elevated grinding wheel velocity in combination of a higher workpiece speed can increase the machining rate while maintaining the desired surface integrity. After a series of grinding tests, a comprehensive measurement has been done to study the surface damage by the surface roughness, the microscope profile and the X-ray diffraction. In particular, the effect of the grinding parameters on the ground surface are analyzed and reported.

Research on Workpiece Surface Temperature and Surface Quality in High-Speed Cylindrical Grinding and its Inspiration

The temperature in cylindrical grinding contact zone is difficult for measurement. Relative to the fixed workpiece in surface grinding, the workpiece rotation in cylindrical grinding brings challenges to the temperature measurement. In grinding titanium alloy, more heat will be generated, and due to the poor thermal conductivity of this material, it is easy to make the high temperature rise in the grinding zone. The high surface temperature and its distribution along the depth of the workpiece have great impacts on the grinding burn, metamorphic layer and residual stress. In order to improve the surface quality of machined parts, based on the undeformed chip thickness, this paper proposed a quadratic curve heat flux distribution model to predict the surface temperature distribution in the grinding of titanium alloy (TC4). Experimental results showed that the quadratic curve model under the condition of the measured grinding power, can predict the temperature distribution in the cylindrical grinding zone. Meanwhile, it specifically discussed the impact of the wheel speed on the TC4 surface roughness and the stress distribution, and found the "high-speed" definition in high-speed grinding should be distinguished from the traditional way only judged by the wheel speed, different workpiece materials should be with different "speed" ranges for acquisition of better machining quality.

Study on the Simulation Model and High-Speed Characteristics of Cylindrical Grinding

The existing research shows that high-speed grinding is the main way to machining the common materials and difficult-to-machine materials efficiently and critically. However, the research on mechanism and high-speed characteristics of high-speed cylindrical grinding is few searched. Based on three-dimensional simulation software DEFORM-3D, the simulation model of high speed cylindrical grinding with single grit was established, and the relevant experiment of 3D simulation for high speed cylindrical grinding process was processed. In this paper, the impact of the grinding parameters, such as wheel speed and depth of cut on the grinding force and grinding temperature is explored through analyzing the variation of strain rate, grinding force and temperature, and found that the increasing strain rate can lead to the increase in grinding force and temperature. According to the simulation experiment results, the control model of grinding temperature for prediction of grinding temperature and optimization of grinding parameters, is analyzed and developed in the end. The engineering experiment, conducted on the high speed cylindrical grinder and measured grinding temperature with thermal infrared imager, has been carried out in this study. Engineering and simulation experiments results show good match, for grinding temperature would decline with the increasing wheel speed when the grinding depth keeps constant, and thus can reduce grinding burn, improve the surface quality of workpiece.

Analysis and Experimental Investigation of Chatter Suppression in High-Speed Cylindrical Grinding

In this paper, the variable speed grinding experiments at high speed have been studied systematically, and the method of improving the surface quality of high-speed grinding has been discussed on the basis of analysis of the chatter and the stability of the high-speed grinder. Through the variable speed grinding experiments at high speed, the vibration characteristics were measured by the vibration energy, and the power spectrum were analyzed by the maximum entropy spectral estimation of the vibration signals in time series. The results confirm that the chatter of high-speed grinding can be suppressed by the variable speed grinding to a certain extent.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.